ECU Compatibility

I'm swapping a Z6 into my rex tomarrow, but unfortunately i don't have the P28 ECU for it yet. Is it possible to run the motor with the PM6 ECU? (stock si ecu) Will it make it run bad? will it ruin the motor? will it run at all? will it plug-in to the wiring harness? or will it just run non-vtec and loose a little bit of horse power just for the time being (like a week or so) until i can get the right ecu?